Rocker chair



P. s. FLETCHER RocKER CHAIR Filed June 20, 1960 June 11, 1963 UnitedStates Patent 3,093,409 ROCKER CHAIR Peter S. Fletcher, Delray Beach,Fla., assigner to Anton Lorenz, Boynton Beach, Fla. Filed June 20, 1960,Ser. No. 37,402 5 Claims. (Cl. 297-89) The present invention relates toreclining chairs, and in particular to a rocker type of reclining chairwhich includes a rst or normal sitting position wherein the chair may berocked and a second tilted or sitting position wherein the chair may berocked. Advantageously, the chair may incorporate a leg-rest which ismoved into an elevated leg-supporting position in dependence uponmovement of the chair into the tilted sitting position wherein the chairis rocked with the leg-rest in its elevated leg-supporting position.

It is generally known to provide a rocker chair which comprises a basewhich is engaged by a rocker member having a body-supporting unitthereon, such that the chair occupant may, when seated in thebody-supporting unit, rock back and forth. It has further been suggestedthat such rocker chair be provided with a leg-rest which is mounted onthe chair for movement from a stored or retracted position to anelevated leg-supporting position. In such chair, the leg-rest may eitherbe spring-biased to move to the extended leg-supporting position uponrelease of a locking mechanism by an actuating handle, or may bemanually moved into the extended leg-supporting position by manipulationof a handle. Further, chairs of this type have been provided with meansfor locking the same in a tilted back position, with the legrestextended or retracted in accordance with the desires lof the chairoccupant, such means usually requiring the provision of a second handleto be operated by the chair occupant. Apart from the inherent complexityintroduced by the provision of independent means for manually releasingor actuating the leg-rest and/or locking the chair in one of a number ofpositions, the need for one or more handles to be operated by the chai-roccupant to establish the various chair positions is a deterrent to thewidespread commercial acceptance of a rocker chair of this type. Theaverage consumer, particularly in the field of home furnishings, isreluctant to purchase or use a chair which is not completely automaticand requires the facility to operate mechanisms associated with thechair, no matter how simple such mechanisms may be in the use of thechair (Le. the manipulation of one or more handles). Quite apart fromthis, the handles, which must be external to the chair proper and in aneasily accessible location, for example at the side of the chair frame,are relatively unsightly and are tell-tale evidence of the mechanicalnature of the chair.

Broadly, i-t is an object of the present invention to provide a rockertype of reclining chair which obviates one or more of the aforesaiddiiculties. Specifically, it is within the contemplation of the presentinvention to provide a rocker chair which is constructed to establish airst sitting position wherein the chair occupant may rock, and by merelypushing against the chair frame may establish a tilted sitting positionwherein a leg-rest incorporated in the chair is moved to an elevatedleg-supporting position, and in which tilted sitting position the chai-roccupant may rock. Such tilted sitting position is particularlyappropriate for reading, sewing, television viewing and like activities.

' In accordance with an illustrative embodiment demonstrating objectsand features of the present invention, there is provided a rocker chaircomprising a base, a rocker member having a rocker cam engaging the baseto rock thereon, and a seat and back-rest unit mounted 3,093,409Patented .lune 1l, 1963 'lee on the rocker member for rearward movementout of a normal sitting position. The rocker cam is operable in thenormal sitting position to rock the rocker member and the unit uponactuation by the occupant of the chair to realize a first rockingmotion. The rocker cam is 0perable during rearward movement of the unitto tilt the unit on its base to provide a stable tilted sitting positionwherein the rocker cam is operable to provide a second rocking motionsimilar to the rst motion but centered about the tilted sitting positionof the rocker member 0n the base. As a feature of the invention, aleg-rest is provided which is movable from a stored or retractedposiltion to an elevated leg-supporting position, with provision formoving the leg-rest to the elevated leg-supporting position independence on the rearward movement of the unit.

When in the normal sitting position, the chair occupant can rock or tiltback by pushing against the floor with his or her feet. When the chairoccupant desires to establish the tilted sitting position (commonlyreferred to in the trade as the T.V. position), the occupant merelypushes with his or her hands on the arm rests of the chair such as t0move the seat and back-rest unit rearwardly, which in turn tilts the armrests and the unit into the tilted sitting position and moves theleg-rest into the elevated leg-supporting position. To achieve a rockingmotion in the tilted sitting or T.V. position, it is merely necessaryfor the chair occupant to rock his or her body, or a part thereof, andthe entire structure, including the seat and back-rest unit, theleg-rest and the arm rests, Will rock on the chair base.

The above brief description, as Well as Ifurther objects, features andadvantages of the present invention, will be more fully appreciated byreference to the following detailed description of an illustrativeembodiment according to the present invention, when taken in conjunctionwith the accompanying drawings, wherein:

FIG. l is a side elevational view, with the adjacent arrn rests removed,and with parts broken away and sectioned, showing an improved rockerchair embodying features of the present invention, the full linesshowing the first or normal sitting position, and the respective dotdashand dash lines and the directional arrows showing the chair rockedrearwardly and forwardly; and

FIG. 2 is a side elevational view similar to FIG. 1 but showing thechair in the tilted sitting or T.V. position, with the leg-rest movedinto the elevated leg-supporting position, the dot-dash and dash ylinesand the directional arrows showing the chair rocked rearwardly andforwardly.

Referring now specically to the drawings, there is shown in FIGS. l and2 a rocker chair constructed in accordance with the present invention,and generally designated by the reference numeral 10, which comprises abase 12, a chair frame or support 14 and a seat and back-rest orbody-supporting unit 16 having a back-rest 18 and a seat 20 which ismounted on the support 114 for movement between a first or normalsitting position illustrated in FIG. l, and a second tilted or T.V.position shown in FIG. 2. Disposed beneath the forward end of the seat20 of the unit 16 is a leg-rest 22 which is mounted by a leg-restmounting and control arrangement 24 for movement to an extended andelevated leg-supporting position forwardly of the seat 20 in response tomovement of the unit 16 from the normal sitting position of FIG. l intothe tilted sitting position of FIG. 2.

In this illustrative embodiment, the base 12 includes a pedestal havingfour legs 26 which extend radially and downwardly from a swivel assembly28. The swivel assembly, which is of conventional construction andsubject to a latitude of variation and change, includes a stationaryplate serving as a stationary raceway, to which the legs 26 are secured.Substantially coextensive with the stationary plate Sii is a movableplate 32 which serves as a movable raceway, with ball bearings 34 beinginterposed therebetween. Axially of the movable plate 32 is a dependingstub shaft 36 which is received within an appropriate bearing openingcentrally of the stationary plate 30, and is held against removal fromthe assembled position by a lock nut or washer (not shown). Although thebase -12 has been illustrated as incorporating a swivel assembly 28, itwill be appreciated that the chair has useful application with orwithout the swivel assembly.

The chair frame 14 includes opposed upstanding spaced arm rests 38 whichare interconnected by one or more cross braces, such as the intermediatecross brace 4G and the rear cross brace 42. Resting on the cross braces4G, 42, and secured thereto, is a rocker member 44 which is providedwith a curved rocker cam 46 on its under surface. It will be appreciatedthat the rocker member 44 and rocker cam 46 is a unitary part of thesupport 14, and in this sense the entire support 14 may be considered toprovide a rocker member. The rocker cam 46 rests upon and engages a basemember 48 having a camsupporting surface 50 on its upper face. Therocker cam 46 makes successive contact with the cam-supporting surfaceSi) as the chair is rocked back and forth in the positions illustratedin FIGS. l and 2 respectively. Interposed between the base member 4S andthe rocker member 44 are front and rear pairs of springs (only one ofeach of the front and rear pairs of springs being shown in the drawingsand designated by the reference numerals 52, 54). The springs arereceived in respective cut-outs 44a, 48a, provided in the rocker member44 and in the base member 43. The cut-outs 44a, 48a open through therocker cam 46 and cam-engaging surface Sil, and together define ahousing for the front and rear pairs of springs 52, 54. Suitable means(not shown) are provided for securing the opposite ends of the springs52, 54 to the top and base Walls respectively of the cut-outs 44a, 48a,of the rocker member 44 and the base member 48.

A control linkage mounts the body-supporting unit 16 on the rockermember 46 for rearward movement from the rst or normal sitting positionof FIG. 1 to the second or tilted sitting position of FIG. 2. In thisillustrative embodiment, the control linkage includes a front guidinglink 56 disposed in an upwardly and forwardly inclined attitude in thesitting position of the chair and having a front pivotal mount 58 at itslower end on the rocker member 44 and a front pivotal connection 60 atits upper end to the seat 2t) of the body-supporting unit 16. Spacedrearwardly of the front guiding link 56 is a rear guiding link 62 whichis disposed in a forwardly inclined attitude in the sitting position ofthe chair and has a rear pivotal mount 64 on the rocker member 44 and arear pivotal connection 66 to the seat 20 of the body-supporting unit16. The control linkage, including the front and rear guiding links 56,62 and their respective pivotal mounts and pivotal connections betweenthe rocker member 44 and the body-supporting unit 16, mounts thebodysupporting unit for rearward movement with substantially no changein the pitch of the body-supporting unit 16 relative to the rockermember 44. Further, as will be appreciated by progressively inspectingFIGS. l and 2, and as will be speciically described, the rocker cam 46of the rocker member 44 stabilizes at a different position on thecam-engaging surface 50 of the base member 48 in the positionillustrated in FIG. 2 such as to impart, in conjunction with the controllinkage, the desired pitch to the body-supporting unit in the FIG. 2position. The center of gravity of the body-supporting unit 16 in thefirst or normal sitting position of FIG. l, establishes a first stableposition of the rocker member 44 on the base member 48 such that thebody-supporting unit 16 may be rocked about the rst stable position, asshown in FIG. l by the dot-dash and dash line showings. In thisconnection, it is to be noted that the front and rear pairs of springs50, S4 are substantially unstressed in the stable position illustratedby the full lines in FIG. l, with the rear pair of springs 54 beingplaced in compression when the chair is rocked rearwardly to thedot-dash position, and with the front pair of springs 52 beingsimultaneously placed in tension. Conversely, as the chair is rockedforwardly, the front pair of springs 52 is placed in compression and therear pair of springs 54 is placed in tension.

Movement of the body-supporting unit 16 rearwardly on 4the rocker member44 under the control of the control linkage -is effective to shift thecenter of gravity of the body-supporting unit rearwardly as thebodysupporting unit moves into the second or tilted sitting positionillustrated in FIG. 2. In this illustrative embodiment, the front andrear guiding links 56, `62 respectively move through ascending arcs andthen move through descending arcs into the position illustrated in FIG.2 wherein a stop 68 on the rear guiding link 62 abuts the rocker member44 to block further movement of the four-bar `control linkage whichincludes, as a relatively stationary link thereof, the portion of therocker member 44 intermediate the front and rear pivotal mounts 58, 64,and as movable links thereof, the front guiding link 56, the portion ofthe seat intermediate the front `and rear pivotal connections 60, 66 andthe rear guiding link 62. The rearward movement of the center of`gravity includes a rst or locked phase during which the center ofgravity rises such that there is a tendency for the body-supporting unitto remain in the rst or normal sitting position of FIG. 1, `and furtherincludes a second or self-balancing phase during which the center ofgravity is lowered to compensate for the movement of the leg-rest 22into the elevated leg-supporting position. The locked phase ischaracterized by a definite, but small, rise in lthe center of gravityof the unit and chair occupant at the start of the rearward movementfrom the normal sitting position, as shown in FIG. 1, to the tiltedsitting position, as shown in PIG. 2, which rise Itends to urge thebody-supporting unit 16 into the normal sitting position andnecessitates effort on the part of the occupant to move the center ofgravity upwardly through the locked phase and into the self-balancingphase wherein the center of gravity is lowered. The selfbalancing phaseprovides for a movement of the bodysupporting unit 16 which will balancethe movement of the leg-rest 22 as it carries the legs of the chairoccupant upwardly to the elevated leg-supporting position forwardly ofthe seat 20. This motion is characterized by a dropping of the center ofgravity of the unit 16 and the part of the body of the chair occupantsupported thereon as the leg-rest 22 and the legs of the chair occupantare moved upwardly. In determining the path of movement of the center ofgravity during the successive locked and self-balancing phases, it willbe appreciated that the whole weight of the body of the chair occupantis on the body-supporting unit 16 during the rst or locked phase andonly part of the body of the chair occupant is on the body-supportingunit 16 during the second or self-balancing phase. Substantially nochange in pitch or tilt is imparted to the unit 16 by the controllinkage in either of the phases, 'in .that the change in pitch isproduced almost completely by the tilting action of the rocker member 44under the influence of `the rearward shifting of the center of gravityof the chair occupant's body and of the weight of the body-supportingunit 16. Although a simple lfour-bar control linkage has been shown inthis illustrative form of the invention, it will be appreciated thatother types of linkages and their equivalent pin-and-slot guidingmechanisms may be employed in the chair to establish first and secondstable positions for the rocker member 44 on the base member 48 in whichstable positions the body-supporting unit may be rocked under control ofthe chair occupant. As is seen in FIG. 2, the center of gravity of thebodysupporting unit in the tilted sitting or T.V. position is disposedsufficiently rearwardly of the center of gravity in the normal sittingposition of lFIG. '-1 to establish the second stable position aboutIwhich the body-supporting unit 16 may be rocked with the leg-rest Z2elevated. In the -second stable position illustrated in FIG. 2, the rearpair of springs '4 are placed in compression, while the front .pair ofsprings 52 are placed in tension, with the rocker member 48, the chairframe -14 and the bodysupporting unit 16 rocking back and for-th aboutsuch second stable position. 'I'he degree of tilting of the rockermember 48 and of the unit 16 may be readily controlled by the amount ofrearward shift of the center of gravity inciden-t to movement of thebody-supporting unit from the FIG. 1 position to the FIG. Z position. Inthe previous reference to the center of gravity, it will be appreciatedthat the design must take into account Ithe weight of theybody-supporting unit and its associated `frame and linkage mechanisms,as well as the weight of the average chair occupant.

In this illustrative embodiment, the leg-rest mounting and control4arrangement 24 includes three pairs of mounting links having theiradjacent ends pivotally connected together, with the links crossing overeach other and being pivotally mounted on the seat and pivotallyconnected to the leg-rest 22 to provide the well known lazy tong orscissor type of leg-rest mounting linkage. It will of course beappreciated that the leg-rest mounting linkage is subject to Va latitudeof modication `and change as will be `apparent by considering thepatents owned by the assignee of the instant application related toleg-rest mounting linkages. Specifically, the leg-rest mounting linkage24 includes a iirst link pair 70, 72 having their adjacent endspivotally connected at a pivotal connection 74, a second link pair 76,78 having their adjacent ends pivotally connected at a pivotalconnection 80, and a third link pair 82, 84 having their adjacent endsinterconnected at a pivotal connection `86. The rst link 70 of the irstlink pair has a pivotal mount 88 on the forward portion of the seat,while the first link 76 ot the second link pair has a pivotal connection90 on the seat at Va point spaced forwardly of the pivotal connection`88. The second link 72 of the iirst link pair crosses over the lirstlink 76 of the second link pair and has a pivotal connection 92 thereto,with the forward end of the second link 72 of the first link pair 70, 72having a pivotal connection '94 to the rst link 82 of the third linkpair. The second link 78 of the second link pair has a pivotalconnection 96 to the rst link 82 of the third lin-k pair intermediateits ends and a pivotal connection l90 at its -forward end to theleg-rest 22. Finally, the second link S4 of the third link pair has apivotal connection 100' at its forward end to the leg-rest 22. Theleg-rest mounting and control arrangement is completed by a directactuating link 102 which has a pivotal connection '4 at its forward endto the link 70 and a pivotal mount 106 on the chair :frame 14. Inresponse to rearward movement of the body-supporting unit 16 relative tothe chair frame 14 and to the rocker member 44 which is a part thereof,the pivotal connections 88, 90 of the leg-rest mounting linkage will bedisplaced rearwardly and will turn to an upward and forward 4arc tothereby move -the leg-rest Z2. from its stored position illustrated inFIG. 1 to an elevated leg-supporting position spaced forwardly of theseat 20 of the bodysupporting unit 116.

In order to facilitate a more thorough understanding of the presentinvention, lreference will now be made to a typical sequence ofope-rations:

When the chair is in the normal sitting position illustrated in FIG. lwith the leg-rest 22 in the retracted or stored position, the chairoccupant can rock back and forth or move the body-supporting unit 16 toa tilted attitude, by pushing against the floor with his or her feet, asshown by the dotted line showings in FlG. 2

and indicated by the directional arrows. When the chair occupant desiresto move the body-supporting unit 16 into the tilted sitting or T.V.position, the occupant pushes with his or her hands on the arm rests orsides 38 of the chair and the body-supporting unit 16 will moverearwardly to bring the body-supporting unit into the tilted sittingposition. Incident to such rearward movement, the leg-rest 22 moves tothe elevated legsupporting position and the rocker cam 46 of the rockermember 44 assumes a second stable position on the camengaging surface 50of the base member 48. In such second stable posit-ion, with theleg-rest 2.2r elevated and the body-supporting unit V16 pitched inaccordance with the degree of rearward shift of the center of gravity ofthe unit, the entire assembly of the body-supporting unit 16, theleg-rest 22, the chair 4frarne 14 and the associated -mechanisms may berocked back and forth, as shown by the dotted line showings in FIG. 2and indicated -by the directional arrows. When the chair occupantdesires to restore the chair to the normal sitting position, it ismerely necessary to lean forwardly and push against the leg-rest, whichwill cause the chair to return from the T.V. position illustrated inFIG. 2 to the normal sitting position illustrated in FIG. l, with acorresponding movement of the center of gravity through theself-balancing and locking phases respectively.

From the foregoing, it will be appreciated that there has been provided,in accordance with the present invention, a rocker chair which has twostable rocking positions, namely a iirst position wherein thebody-supporting unit is in a substantially upright attitude, with thelegres-t of the chair stored, and a second position wherein thebody-supporting unit is tilted back at an appropriatey pitch relative tothe support for television Iviewing, reading and the like, and with theleg-rest elevated to a legsupporting position. Movement to either of thepositions by the chair occupant is achieved in a simple manner,requiring no manual manipulation such as the operation of handles or thelike. Further, the mechanisms employed for establishing the mode ofoperation of the chair and its respective stable Arocking posit-ionsarerelatively simple, thereby facilitating mass production manufacture atrelatively -low unit cost, and ease of assembly.

A latitude of modification, change and substitution is intended in theforegoing disclosure and in some instances some features of theinvention will be employed without a corresponding use of otherfeatures. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with the spirit and scopeof the invention herein.

What I claim is:

l. A rocking chair comprising a base, a body-supporting unit, a rockermember mounted on said base for rocking thereon, mounting means mountingsaid bodysupporting unit on said rocker member for rearward movementthereon from a normal sitting position to a tilted sitting position, aleg-rest, a leg-rest control linkage operatively connected between saidbody-supporting unit and said rocker member to move said leg-rest from aretracted position to an elevated leg-supporting position in response tosaid rearward movement of said bodysupporting unit on said rocker memberto said tilted sitting position incident to rearward pressure againstsaid back-rest by the chair occupant, said body-supporting unit and saidrocker member when in said normal sitting position with said leg-rest insaid retracted position having a tirst stable equilibrium position andbeing rockable on said lbase lforwardly and rearwardly about said firststable equilibrium position under control of the chair occupant, therearward movement of said bodysupporting unit relative to said rockermember under cont-rol of said mounting means causing said rocker memberto rock rearwardly to assume a second stable equilibrium positionrelative to said base, the combined effect of the rearward rocking ofsaid rocker member to said second stable equilibrium position and therearward movement of said body-supporting unit under control of saidmounting means causing said bodysupporting unit to assume said tiltedsitting position, said leg-rest being moved to said elevatedleg-supporting position in response to the rearward movement of saidbodysupporting unit into said tilted sitting position, saidbodysupporting unit and rocker member when ,in said tilted sittingposition with said leg-rest in said elevated legsupporting positionbeing rockable on said base forwardly and rearwardly about said secondstable equilibrium position of said rocker member `on said base u-nde-rcontrol of the chair occupant.

2. A rocking chair according to claim 1 wherein the movement of saidbody-supporting unit rearwardly relative to said rocker member undercontrol lof said mounting means is effective to shift the center ofgravity of said body-supporting unit rearwardly, said rocker memberengaging said base at a first location in said normal sitting positionof said body-supporting unit, said rocker member engaging said base at asecond location spaced behind said -rst location in said tilted sittingposition.

3. A rocking chair according to claim 2 wherein the rearward shift ofsaid center of gravity includes a locked phase during which said centerof gravity rises such that there is a tendency for said body-supportingunit to remain in said first sitting position when said body-supportingunit is rocked therein and further includes a selfbalancing phase duringwhich said center of gravity is lowered `to compensate for the movementof said legrest into said elevated leg-supporting position.

4. A rocking chair comprising a base, a body-supporting unit, a rockermember mounted on said base for rocking thereon, a four-bar mountinglinkage mounting said body-supporting unit on said rocker member forrearward movement thereon from a normal sitting position to a tiltedsitting position, Ia leg-rest, a leg-rest control linkage operativelyconnected between said vbody-supporting unit and said rocker ymember tomove said leg-rest from a retracted position to an elevatedleg-supporting position in response to said rearward movement of saidbody-supporting unit on said rocker member to said tilted .sittingposition incident to rearward pressure against said back-rest by thechair occupant, said body-supporting unit and said rocker member when insaid normal sitting position with said leg-rest -n said retractedposition `having a first stable equilibrium position and being rockableon said base forwardly Aand rearwardly about said first stableequilibrium position under control of the chair occupant, the rearwardmovement of said body-supporting unit relative to said rocker memberunder control of said mounting linkage causing said -rocker member torock rearwardly to assume a second stable equilibrium position relativeto said base, the combined effect of the rearward rocking of said rockermember to said second stable equilibrium position and the rearwardmovement of said `body-supporting unit under control of said mountinglinkage causing said body-supporting unit to assume said tilted sittingposition, said leg-rest being moved to said elevated leg-supportingposition in response to the rearward movement of said 'body-supportingunit into said tilted sitting position, lsaid body-supporting unit androcker member Awhen yin said 4tilted sitting position with said legr-estin said elevated leg-supporting position being rockable von said ybaseforwardly and rearwardly about said second stable equilibrium positionof said rocker member on said base under control of lthe chair occupant.

5. A rocker chair according to claim 4 including a pedestal and a swivel`interposed fbetween said pedestal and said base such that said base maybe turned about a vertical axis when said body-supporting unit is insaid sitting positions.

References Cited in the file of this patent UNITED STATES PATENTS2,940,510 Schliephacke June 14, 1960 2,951,528 Maurer Sept. 6, 19602,963,077 Knabusch et al Dec. 6, 1960 FOREIGN PATENTS 498,671 CanadaDec. 22, 1953

1. A ROCKING CHAIR COMPRISING A BASE, A BODY-SUPPORTING UNIT, A ROCKERMEMBER MOUNTED ON SAID BASE FOR ROCKING THEREON, MOUNTING MEANS MOUNTINGSAID BODYSUPPORTING UNIT ON SAID ROCKER MEMBER FOR REARWARD MOVEMENTTHEREON FROM A NORMAL SITTING POSITION TO A TILTED SITTING POSITION, ALEG-REST, A LEG-REST CONTROL LINKAGE OPERATIVELY CONNECTED BETWEEN SAIDBODY-SUPPORTING UNIT AND SAID ROCKER MEMBER TO MOVE SAID LEG-REST FROM ARETRACTED POSITION TO AN ELEVATED LEG-SUPPORTING POSITION IN RESPONSE TOSAID REARWARD MOVEMENT OF SAID BODYSUPPORTING UNIT ON SAID ROCKER MEMBERTO SAID TILTED SITTING POSITION INCIDENT TO REARWARD PRESSURE AGAINSTSAID BACK-REST BY THE CHAIR OCCUPANT, SAID BODY-SUPPORTING UNIT AND SAIDROCKER MEMBER WHEN IN SAID NORMAL SITTING POSITION WITH SAID LEG-REST INSAID RETRACTED POSITION HAVING A FIRST STABLE EQUILIBRIUM POSITION ANDBEING ROCKABLE ON SAID BASE FORWARDLY AND REARWARDLY ABOUT SAID FIRSTSTABLE EQUILIBRIUM POSITION UNDER CONTROL OF THE CHAIR OCCUPANT, THEREARWARD MOVEMENT OF SAID BODYSUPPORTING UNIT RELATIVE TO SAID ROCKERMEMBER UNDER CONTROL OF SAID MOUNTING MEANS CAUSING SAID ROCKER MEMBERTO ROCK REARWARDLY TO ASSUME A SECOND STABLE EQUILIBRIUM POSITIONRELATIVE TO SAID BASE, THE COMBINED EFFECT OF THE REARWARD ROCKING OFSAID ROCKER MEMBER TO SAID SECOND STABLE EQUILIBRIUM POSITION AND THEREARWARD MOVEMENT OF SAID BODY-SUPPORTING UNIT UNDER CONTROL OF SAIDMOUNTING MEANS CAUSING SAID BODYSUPPORTING UNIT TO ASSUME SAID TILTEDSITTING POSITION, SAID LEG-REST BEING MOVED TO SAID ELEVATEDLEG-SUPPORTING POSITION IN RESPONSE TO THE REARWARD MOVEMENT OF SAIDBODYSUPPORTING UNIT INTO SAID TILTED SITTING POSITION, SAIDBODYSUPPORTING UNIT AND ROCKER MEMBER WHEN IN SAID TILTED SITTINGPOSITION WITH SAID LEG-REST IN SAID ELEVATED LEGSUPPORTING POSITIONBEING ROCKABLE ON SAID BASE FORWARDLY AND REARWARDLY ABOUT SAID SECONDSTABLE EQUILIBRIUM POSITION OF SAID ROCKER MEMBER ON SAID BASE UNDERCONTROL OF THE CHAIR OCCUPANT.